A spoiler-free review of the first episode of “The Walking Dead: Michonne,” a new miniseries from Telltale Games. Has the studio that’s widely regarded as the premier creator of episodic interactive drama lost a step? Could “Michonne” learn something from “Life Is Strange” (6:03)? Then, why “XCOM 2” should have been more like “Invisible, Inc.” (13:14)